Gene regulatory network reconstruction using single-cell regulatory network inference and clustering (SCENIC)35 revealed differentially activated transcription factors (TFs) STAT1, IRF2 and PRDM1 in COVID-19 (Fig. 2c), whereas bacterial ARDS neutrophils had increased prototypical granulocyte TFs, such as CEBPA, CEBPB and STAT5B, and less defined factors such as NFE2 (Fig. 2c; Online Atlas). The gene discussed is IRF2; the disease is acute respiratory distress syndrome.